With the discovery of problems about the lack of understanding on pesawat sederhana subject matter science subject, then teachers are required to make learning more varied. But in fact the teacher is still using the book packpage, sometimes the teacher also create a picture of supporting images, but the students are still difficult to understand the exiting subject matter. Textbooks contain only text and images, so it can not directly explain about the material this is audio visual. therefoe, this study aims develop a viable and effective media CAI in subject IPA, in the subject matter pesawat sederhana for stundent of class VIII SMPN 14 Surabaya. This type of research is the research of development. Data were collected using an instrument interview, questionnaire, and test. Instruments interviews to learning expert, subject matter experts , and media experts, questionnaires and tests aimed at students of class VIII SMPN 14 Surabaya. The development model used is a ADDIE model.Types data obtained in the form of quantitative data obtained from questionnaires and student test, as well as qualitative data obtained from interviews of learning expert, material expert, and media expert. This type of research is experimented with the design pretest-posttest control group design. Based on the result of the analysis that has been done, it can be concluded that validation result of the learning experts, material experts, and media experts worthy of use with revision. The result of questionnaire of product test to student of class VIII SMPN 14 Surabaya, it can be concluded that : (a) the result of individual trial percentage 97%(very good), (b) result of small group trial 98%(very good). With these result CAI media is feasible to use. T test analysis is done twice that is compare pretest result of experiment group and control group, second compare result of posttest experiment group and control group. The result of pretest analysis obtained tcount<ttabel (0,506<2,000) means there is no significant difference between the two groups, and the students initial ability same. While the result of posttest analysis is obtained tcount>ttabel (5,64>2,000) means there is significant difference between result of learning of both group. This suggest that the media CAI in the subject IPA subject matter pesawat sederhana is effective